Copyright protection based on hidden copyright information

ABSTRACT

Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage media, for hiding copyright information in printable materials. One of the methods includes generating, by a computing device, a unique identifier (ID) based on copyright information associated with digital content, wherein the copyright information and the digital content are recorded on a blockchain of a blockchain network; determining one or more features associated with one or more printable materials; and converting the unique ID to a digital watermark based on the one or more features, the digital watermark not being apparent to an unaided human eye when printed on the one or more printable materials and enabling retrieval of the copyright information from the blockchain based on the unique ID.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT Application No.PCT/CN2019/087646, filed on May 20, 2019, which is hereby incorporatedby reference in its entirety.

TECHNICAL FIELD

This specification generally relates to copyright protection based onblockchain technology.

BACKGROUND

Distributed ledger systems (DLSs), which can also be referred to asconsensus networks, and/or blockchain networks, enable participatingentities to securely, and immutably store data. DLSs are commonlyreferred to as blockchain networks without referencing any particularuser case. DLS technology creates a transparent chain-of-records byallowing all parties to a transaction to verify what will be enteredonto a ledger, and prevent any party from changing the ledger after thetransaction is entered. Each transaction or block of transactions istransmitted to all the participants in the blockchain network and isverified by each participant node before adding to the blockchain.

With the advancement of digital technologies, online digital content canoften be reproduced, edited, recorded, and distributed by Internetusers. In some cases, such uses can violate copyright of the creator orowner of the content. New technologies can also make management andprotection of copyrighted content difficult. For example, suchtechnologies can enable copies of copyrighted content to be rapidlyproduced and spread to large numbers of users, which can significantlyaffect the economic interests of the copyright holder.

DLS technology creates a secure, time-stamped, and immutablechain-of-records, making it well-suited to protect against copyrightinfringement. For example, a distributed ledger containing the copyrightholder's information and update history relating to the copyrightedcontent can be used to determine ownership or infringement of thecontent.

However, when only a portion of copyrighted content is used byunauthorized users, it can be difficult to identify that the usedportion is part of a copyrighted work. Therefore, it would be desirableto embed copyright information in the background, foreground, or thecontent itself, such that copyrighted material can be more easilyidentified.

SUMMARY

This specification describes technologies for hiding copyrightinformation. These technologies generally involve generating a uniqueidentifier (ID) based on copyright information associated with digitalcontent, determining one or more features associated with one or moreprintable materials; and converting the unique ID to a digital watermarkbased on the one or more features, where the digital watermark not beingapparent to an unaided human eye when printed on the one or moreprintable materials and enabling retrieval of the copyright informationfrom the blockchain based on the unique ID.

This specification also provides one or more non-transitorycomputer-readable storage media coupled to one or more processors andhaving instructions stored thereon which, when executed by the one ormore processors, cause the one or more processors to perform operationsin accordance with embodiments of the methods provided herein.

This specification further provides a system for implementing themethods provided herein. The system includes one or more processors, anda computer-readable storage medium coupled to the one or more processorshaving instructions stored thereon which, when executed by the one ormore processors, cause the one or more processors to perform operationsin accordance with embodiments of the methods provided herein.

It is appreciated that methods in accordance with this specification mayinclude any combination of the aspects and features described herein.That is, methods in accordance with this specification are not limitedto the combinations of aspects and features specifically describedherein, but also include any combination of the aspects and featuresprovided.

The details of one or more embodiments of this specification are setforth in the accompanying drawings and the description below. Otherfeatures and advantages of this specification will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of an environment that canbe used to execute embodiments of this specification.

FIG. 2 is a diagram illustrating an example of an architecture inaccordance with embodiments of this specification.

FIG. 3 is a flowchart illustrating an example of a process that can beexecuted in accordance with embodiments of this specification.

FIG. 4 depicts an example of a content processing process in accordancewith embodiments of this specification.

FIG. 5 depicts an example of a blockchain transaction record inaccordance with embodiments of this specification.

FIG. 6 depicts an example of a copyright infringement determinationprocess in accordance with embodiments of this specification.

FIG. 7 depicts an example of a process that can be executed inaccordance with embodiments of this specification.

FIG. 8 depicts examples of modules of an apparatus in accordance withembodiments of this specification.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

This specification describes technologies for hiding copyrightinformation. These technologies generally involve generating a uniqueidentifier (ID) based on copyright information associated with digitalcontent, determining one or more features associated with one or moreprintable materials; and converting the unique ID to a digital watermarkbased on the one or more features, where the digital watermark not beingapparent to an unaided human eye when printed on the one or moreprintable materials and enabling retrieval of the copyright informationfrom the blockchain based on the unique ID.

To provide further context for embodiments of this specification, and asintroduced above, distributed ledger systems (DLSs), which can also bereferred to as consensus networks (e.g., made up of peer-to-peer nodes),and blockchain networks, enable participating entities to securely, andimmutably conduct transactions, and store data. Although the termblockchain is generally associated with particular networks, and/or usecases, blockchain is used herein to generally refer to a DLS withoutreference to any particular use case.

A blockchain is a data structure that stores transactions in a way thatthe transactions are immutable. Thus, transactions recorded on ablockchain are reliable and trustworthy. A blockchain includes one ormore blocks. Each block in the chain is linked to a previous blockimmediately before it in the chain by including a cryptographic hash ofthe previous block. Each block also includes a timestamp, its owncryptographic hash, and one or more transactions. The transactions,which have already been verified by the nodes of the blockchain network,are hashed and encoded into a Merkle tree. A Merkle tree is a datastructure in which data at the leaf nodes of the tree is hashed, and allhashes in each branch of the tree are concatenated at the root of thebranch. This process continues up the tree to the root of the entiretree, which stores a hash that is representative of all data in thetree. A hash purporting to be of a transaction stored in the tree can bequickly verified by determining whether it is consistent with thestructure of the tree.

Whereas a blockchain is a decentralized or at least partiallydecentralized data structure for storing transactions, a blockchainnetwork is a network of computing nodes that manage, update, andmaintain one or more blockchains by broadcasting, verifying andvalidating transactions, etc. As introduced above, a blockchain networkcan be provided as a public blockchain network, a private blockchainnetwork, or a consortium blockchain network. Embodiments of thisspecification are described in further detail herein with reference to aconsortium blockchain network. It is contemplated, however, thatembodiments of this specification can be realized in any appropriatetype of blockchain network.

In general, a consortium blockchain network is private among theparticipating entities. In a consortium blockchain network, theconsensus process is controlled by an authorized set of nodes, which canbe referred to as consensus nodes, one or more consensus nodes beingoperated by a respective entity (e.g., a financial institution,insurance company). For example, a consortium of ten (10) entities(e.g., financial institutions, insurance companies) can operate aconsortium blockchain network, each of which operates at least one nodein the consortium blockchain network.

In some examples, within a consortium blockchain network, a globalblockchain is provided as a blockchain that is replicated across allnodes. That is, all consensus nodes are in perfect state consensus withrespect to the global blockchain. To achieve consensus (e.g., agreementto the addition of a block to a blockchain), a consensus protocol isimplemented within the consortium blockchain network. For example, theconsortium blockchain network can implement a practical Byzantine faulttolerance (PBFT) consensus, described in further detail below.

FIG. 1 is a diagram illustrating an example of an environment 100 thatcan be used to execute embodiments of this specification. In someexamples, the environment 100 enables entities to participate in aconsortium blockchain network 102. The environment 100 includescomputing devices 106, 108, and a network 110. In some examples, thenetwork 110 includes a local area network (LAN), wide area network(WAN), the Internet, or a combination thereof, and connects web sites,user devices (e.g., computing devices), and back-end systems. In someexamples, the network 110 can be accessed over a wired and/or a wirelesscommunications link. In some examples, the network 110 enablescommunication with, and within the consortium blockchain network 102. Ingeneral, the network 110 represents one or more communication networks.In some cases, the computing devices 106, 108 can be nodes of a cloudcomputing system (not shown), or each computing device 106, 108 can be aseparate cloud computing system including a number of computersinterconnected by a network and functioning as a distributed processingsystem.

In the depicted example, the computing systems 106, 108 can each includeany appropriate computing system that enables participation as a node inthe consortium blockchain network 102. Examples of computing devicesinclude, without limitation, a server, a desktop computer, a laptopcomputer, a tablet computing device, and a smartphone. In some examples,the computing systems 106, 108 hosts one or more computer-implementedservices for interacting with the consortium blockchain network 102. Forexample, the computing system 106 can host computer-implemented servicesof a first entity (e.g., user A), such as a transaction managementsystem that the first entity uses to manage its transactions with one ormore other entities (e.g., other users). The computing system 108 canhost computer-implemented services of a second entity (e.g., user B),such as a transaction management system that the second entity uses tomanage its transactions with one or more other entities (e.g., otherusers). In the example of FIG. 1, the consortium blockchain network 102is represented as a peer-to-peer network of nodes, and the computingsystems 106, 108 provide nodes of the first entity, and second entityrespectively, which participate in the consortium blockchain network102.

FIG. 2 depicts an example of an architecture 200 in accordance withembodiments of this specification. The architecture 200 includes anentity layer 202, a hosted services layer 204, and a blockchain networklayer 206. In the depicted example, the entity layer 202 includes threeparticipants, Participant A, Participant B, and Participant C, eachparticipant having a respective transaction management system 208.

In the depicted example, the hosted services layer 204 includesinterfaces 210 for each transaction management system 210. In someexamples, a respective transaction management system 208 communicateswith a respective interface 210 over a network (e.g., the network 110 ofFIG. 1) using a protocol (e.g., hypertext transfer protocol secure(HTTPS)). In some examples, each interface 210 provides communicationconnection between a respective transaction management system 208, andthe blockchain network layer 206. More particularly, the interface 210communicate with a blockchain network 212 of the blockchain networklayer 206. In some examples, communication between an interface 210, andthe blockchain network layer 206 is conducted using remote procedurecalls (RPCs). In some examples, the interfaces 210 “host” blockchainnetwork nodes for the respective transaction management systems 208. Forexample, the interfaces 210 provide the application programminginterface (API) for access to blockchain network 212.

As described herein, the blockchain network 212 is provided as apeer-to-peer network including a plurality of nodes 214 that immutablyrecord information in a blockchain 216. Although a single blockchain 216is schematically depicted, multiple copies of the blockchain 216 areprovided, and are maintained across the blockchain network 212. Forexample, each node 214 stores a copy of the blockchain. In someembodiments, the blockchain 216 stores information associated withtransactions that are performed between two or more entitiesparticipating in the consortium blockchain network.

A blockchain (e.g., the blockchain 216 of FIG. 2) is made up of a chainof blocks, each block storing data. Examples of data include transactiondata representative of a transaction between two or more participants.While transactions are used herein by way of non-limiting example, it iscontemplated that any appropriate data can be stored in a blockchain(e.g., documents, images, videos, audio). Examples of a transaction caninclude, without limitation, exchanges of something of value (e.g.,assets, products, services, currency). The transaction data is immutablystored within the blockchain. That is, the transaction data cannot bechanged.

Before storing in a block, the transaction data is hashed. Hashing is aprocess of transforming the transaction data (provided as string data)into a fixed-length hash value (also provided as string data). It is notpossible to un-hash the hash value to obtain the transaction data.Hashing ensures that even a slight change in the transaction dataresults in a completely different hash value. Further, and as notedabove, the hash value is of fixed length. That is, no matter the size ofthe transaction data the length of the hash value is fixed. Hashingincludes processing the transaction data through a hash function togenerate the hash value. An example of a hash function includes, withoutlimitation, the secure hash algorithm (SHA)-256, which outputs 256-bithash values.

Transaction data of multiple transactions are hashed and stored in ablock. For example, hash values of two transactions are provided, andare themselves hashed to provide another hash. This process is repeateduntil, for all transactions to be stored in a block, a single hash valueis provided. This hash value is referred to as a Merkle root hash, andis stored in a header of the block. A change in any of the transactionswill result in change in its hash value, and ultimately, a change in theMerkle root hash.

Blocks are added to the blockchain through a consensus protocol.Multiple nodes within the blockchain network participate in theconsensus protocol, and perform work to have a block added to theblockchain. Such nodes are referred to as consensus nodes. PBFT,introduced above, is used as a non-limiting example of a consensusprotocol. The consensus nodes execute the consensus protocol to addtransactions to the blockchain, and update the overall state of theblockchain network.

In further detail, the consensus node generates a block header, hashesall of the transactions in the block, and combines the hash value inpairs to generate further hash values until a single hash value isprovided for all transactions in the block (the Merkle root hash). Thishash is added to the block header. The consensus node also determinesthe hash value of the most recent block in the blockchain (i.e., thelast block added to the blockchain). The consensus node also adds anonce value, and a timestamp to the block header.

In general, PBFT provides a practical Byzantine state machinereplication that tolerates Byzantine faults (e.g., malfunctioning nodes,malicious nodes). This is achieved in PBFT by assuming that faults willoccur (e.g., assuming the existence of independent node failures, and/ormanipulated messages sent by consensus nodes). In PBFT, the consensusnodes are provided in a sequence that includes a primary consensus node,and backup consensus nodes. The primary consensus node is periodicallychanged, Transactions are added to the blockchain by all consensus nodeswithin the blockchain network reaching an agreement as to the worldstate of the blockchain network. In this process, messages aretransmitted between consensus nodes, and each consensus nodes provesthat a message is received from a specified peer node, and verifies thatthe message was not modified during transmission.

In PBFT, the consensus protocol is provided in multiple phases with allconsensus nodes beginning in the same state. To begin, a client sends arequest to the primary consensus node to invoke a service operation(e.g., execute a transaction within the blockchain network). In responseto receiving the request, the primary consensus node multicasts therequest to the backup consensus nodes. The backup consensus nodesexecute the request, and each sends a reply to the client. The clientwaits until a threshold number of replies are received. In someexamples, the client waits for f+1 replies to be received, where f isthe maximum number of faulty consensus nodes that can be toleratedwithin the blockchain network. The final result is that a sufficientnumber of consensus nodes come to an agreement on the order of therecord that is to be added to the blockchain, and the record is eitheraccepted, or rejected.

In some blockchain networks, cryptography is implemented to maintainprivacy of transactions. For example, if two nodes want to keep atransaction private, such that other nodes in the blockchain networkcannot discern details of the transaction, the nodes can encrypt thetransaction data. An example of cryptography includes, withoutlimitation, symmetric encryption, and asymmetric encryption. Symmetricencryption refers to an encryption process that uses a single key forboth encryption (generating ciphertext from plaintext), and decryption(generating plaintext from ciphertext). In symmetric encryption, thesame key is available to multiple nodes, so each node can en-/de-crypttransaction data.

Asymmetric encryption uses key pairs that each include a private key anda public key, the private key being known only to a respective node, andthe public key being known to any or all other nodes in the blockchainnetwork. A node can use the public key of another node to encrypt data,and the encrypted data can be decrypted using other node's private key.For example, and referring again to FIG. 2, Participant A can useParticipant B's public key to encrypt data, and send the encrypted datato Participant B. Participant B can use its private key to decrypt theencrypted data (ciphertext) and extract the original data (plaintext).Messages encrypted with a node's public key can only be decrypted usingthe node's private key.

Asymmetric encryption is used to provide digital signatures, whichenables participants in a transaction to confirm other participants inthe transaction, as well as the validity of the transaction. Forexample, a node can digitally sign a message, and another node canconfirm that the message was sent by the node based on the digitalsignature of Participant A. Digital signatures can also be used toensure that messages are not tampered with in transit. For example, andagain referencing FIG. 2, Participant A is to send a message toParticipant B. Participant A generates a hash of the message, and then,using its private key, encrypts the hash to provide a digital signatureas the encrypted hash. Participant A appends the digital signature tothe message, and sends the message with digital signature to ParticipantB. Participant B decrypts the digital signature using the public key ofParticipant A, and extracts the hash. Participant B hashes the messageand compares the hashes. If the hashes are same, Participant B canconfirm that the message was indeed from Participant A, and was nottampered with.

As described above, blockchain can be used to generate an immutable andtransparent chain-of-record that can assist in identification andauthentication of creators or right holders of original copyrightedworks. For example, a transaction related to copyrighted content (e.g.,a content update or newly entered identity information associated withcreator of the content) recorded on the blockchain can be encoded as aunique ID. The unique ID can be invisibly hidden in printable materials(e.g., paper) by adapting to one or more features (e.g., texture, hue,deformation) of the copyrighted content in a manner that does not affectthe visual presentation of the printable materials or the content, andis undiscernible or not readily apparent to an inspecting user.

To determine the copyright holder and identify potential copyrightinfringement, the embedded unique ID can be extracted from the printablematerials to decode the transaction. The transaction can then be used toretrieve a chain-of-record associated with the copyrighted content. Insome embodiments, the chain-of-record can be used to identify acopyright holder, and seek permission from the copyright holder to copy,modify, distribute, or publicly display copyrighted works. In someembodiments, the chain-of-record can also be used to resolve copyrightdispute or determine whether the copyrighted content has been tamperedwith.

FIG. 3 is a flowchart illustrating an example of a process 300 that canbe executed in accordance with embodiments of this specification. Theprocess 300 can be performed by one or more blockchain nodes or acomputing device communicably coupled to the one or more blockchainnodes. For clarity of presentation, the description that followsgenerally describes process 300 in the context of the other figures inthis description. However, it will be understood that process 300 can beperformed, for example, by any system, environment, software, andhardware, or a combination of systems, environments, software, andhardware, as appropriate. In some embodiments, various steps of process300 can be run in parallel, in combination, in loops, or in any order.

At 302, a digital content is identified. The digital content can becontent of a copyrighted work (i.e., copyrighted digital content, orsimply, copyrighted content) associated with a copyright holder.Copyrighted works can be any original or creative works, such asliterary works, motion pictures, choreography, musical compositions,sound recordings, paintings, drawings, sculptures, photographs, computersoftware, radio and television broadcasts, or industrial designs.Copyrighted content can exist in the form of digital data, which can bedigitally transmitted, streamed, contained in computer files, or storedas a transaction record in a blockchain.

At 304, blockchain-based copyright authentication is performed. In someembodiments, copyright authentication can include authenticating a rightholder of copyrighted content. As discussed earlier, blockchain providesan immutable chain-of-record of transactions related to the copyrightedcontent. For example, transactions related to the copyrighted contentcan include the original digital content, timestamps or locations ofcontent creation and distributions, content update or modificationhistory, creatorship, ownership, licensing information, or otherinformation. After a transaction is approved, a corresponding blockchaintransaction ID can be recorded to the corresponding block anddistributed to the distributed ledger of the blockchain network. In someembodiments, the transactions can also be embedded with smart contractinformation associated with an Ethereum blockchain.

The right holder of copyrighted content can be authenticated based ontraversing transaction records of the copyrighted content on theblockchain. For example, a blockchain transaction ID associated with arecord of the copyrighted content on the blockchain can be determined. Achain-of-record associated with the blockchain transaction ID can thenbe traversed until a record on ownership or creatorship associated withthe copyrighted content is identified. The identified owner or creatorof the content recorded on the blockchain can be determined as theauthentic right holder. In some embodiments, the ownership orcreatorship information may not be recorded on the blockchain. In suchcases, the right holder may be authenticated if other information (e.g.,detailed update and modification history) can be provided to matchrecords on the blockchain.

At 306, a unique ID associated with the copyright holder can begenerated. The unique ID can be used to uniquely identify the copyrightholder. In some embodiments, the unique ID can be a public keycertificate issued by a certificate authority (CA). For example, the CAcan be one or more trusted entities of a consortium blockchain. Thecertificate can include the copyrighted content, information about theidentity of the copyrighted holder, and the digital signature of the CA.In some embodiments, the unique ID can include the copyright holder'sidentity information digitally signed by its private key. The copyrightholder can then be identified by decrypting the digital signature withthe public key corresponding to the copyright holder and verified bycomparing the decrypted information to the copyright holder'sinformation in the blockchain.

The copyright holder can be an individual or a business entity. Exampleidentity information of individual copyright holder can include one ormore of the right holder's residence ID, passport number, driver'slicense number, phone number, or name. Example identity information ofbusiness copyright holder can include one or more of businessregistration number, tax ID, registered name, phone number, address, ortrademark.

In some embodiments, the unique ID can be generated based ontransactions associated with the copyrighted content recorded on theblockchain. As discussed earlier, those transactions can include thecopyrighted content, timestamps or locations of content creation anddistributions, content update or modification history, creatorship,ownership, licensing information, etc. The unique ID can be generatedbased on one or more transactions. In some cases, at least a portion ofthe copyrighted content can be used to generate the unique ID, such asby generating a hash value based on the portion of the content. In someexamples, the portion of the copyrighted content preserves theoriginality of the copyrighted, and can be used to identify thecopyrighted content it is extracted from. To identify the copyrightholder, the portion of the copyrighted content can be used to identify ablockchain transaction ID corresponding to the recordation of thecopyrighted content on the blockchain. The blockchain transaction ID canthen be used to retrieve an entire chain-of-record associated with thecopyrighted content to identify the copyright holder. In someembodiments, the unique ID can also be generated based on the one ormore transactions and one or more of the corresponding timestamps andlocations.

In some embodiments, the unique ID can be invisibly embedded in datacarriers as a digital watermark, such that it can be extracted to obtainassociated copyright information. In some embodiments, the unique ID canbe encrypted or hashed to enhance the robustness and security of thedigital watermark. For example, the encryption can be performed based onpublic key encryption using the copyright holder's public key. In someembodiments, the encryption can also be performed based on encryptionschemes such as the Arnold scrambling encryption to adapt to theembedding technique used. By performing encryption, even if an attackerextracts the digital watermark, the associated identity informationcannot be decrypted if the encryption scheme or encryption key isunknown to the attacker.

In some embodiments, timestamps and addresses associated with thetransactions of the copyrighted content can be added to generate theunique ID. The addition of timestamp and address information can furtherensure uniqueness of the ID. The timestamp and address information canalso be used to identify and authenticate the right holder for copyrightinfringement detection and enforcement. In some embodiments, the uniqueID can also be a digital signature generated based on the right holder'sprivate key.

At 308, the unique ID is invisibly embedded. In some examples, theembedded unique ID can be considered invisible if its addition is notnoticeable or visible to naked eyes. In other words, the unique ID canbe considered invisible if the visual difference between the copyrightedcontents before embedding the unique ID and after embedding the uniqueID is not apparent to an unaided human eye. The unique ID can beembedded in copyrighted content, foreground of the copyrighted content,or background of the copyrighted content. The foreground of thecopyrighted content can be a film or screen attached or integrated to aplatform where the copyrighted content is displayed. The foreground ofthe copyrighted content can also be a layer including the unique ID thatis configured not to be rendered by a viewing application. Thebackground of the copyrighted content can be a physical object (e.g.,paper) the copyrighted content is printed on, or a background of avisual representation of an electronic file containing the copyrightedcontent that is rendered on a display.

The invisible embedding of copyrighted content can be performed based ondigital watermarking. Digital watermarking is a technique of using datacarriers to embed copyright information. Data carriers can include text,images, physical or electronic media. The unique ID can be embedded inthe data carriers as an invisible digital watermark. When a copyrightdispute occurs, the unique ID can be extracted from the data carriers toverify the ownership of the copyright.

Digital watermarking techniques can include background brightnessmasking, illuminance masking, texture masking, spatial masking andfrequency masking. Different techniques can be based on differentdigital watermarking algorithms. In some embodiments, digital watermarkembedding can be based on human visual system (HVS) characteristics toachieve visual imperceptibility or invisibility. For example, the humaneyes are more sensitive to the changes in the low intensity pixels thanthe higher intensity ones. In illuminance masking, pixels of digitalcopyrighted content can be scanned to identify those with high intensitylevels. The high intensity pixels can be used to embed the digitalwatermark. Modifications made to the high intensity pixels can bedifficult to perceive by human eyes, such that the digital watermark canbe considered invisibly embedded. Using illuminance masking, the digitalwatermark can be embedded in the entire copyrighted content or a portionof the content. For example, if the copyrighted content is textualcontent, the digital watermark can be embedded in a letter, a word, asentence, or all the way up to the entire textual content.

As another example, in texture masking, the more complex the texture is,the more difficult the human eyes can discern the change of the texture.Therefore, the digital watermark can be embedded to a portion of acopyrighted image or background of copyrighted content with more complextexture to be less perceptible by human eyes.

As yet another example, digital watermarking can be performed based onfrequency masking by transforming the copyrighted content to frequencydomain coefficients based on mathematical transformations such asdiscrete cosine transform (DCT), discrete wavelet transform (DWT), orArnold transform. In frequency masking, intermediary or low frequencycoefficients are normally modified according to the watermarkinformation. Those frequency ranges are less impactful to the appearanceof the original content. The digital watermark (i.e., the unique ID) canbe in the form of a character string. The character string can beconverted to a single binary string. Each bit can be embedded to adjustlower frequency coefficients depending on the transformation techniqueused. In frequency masking, the digital watermark can be dispersed tothe whole copyrighted content, which can increase robustness andinvisibility. Other example mathematical transformations for performingdigital watermarking can include DWT and singular value decomposition(DWT-SVD), least significant bit (LSB), or highly undetectablesteganography (HUGO).

In some embodiments, more than one digital watermarking technique can beused to embed multiple layers of digital watermarks to the data carrier.In such cases, an index of the layers of digital watermarking can alsobe generated and embedded in the data carrier. The index can be used tomore easily extract digital watermarks from the data carriers whenperforming copyright authentication or infringement identification. Insome embodiments, the unique ID can be randomized or mixed with a randomsignal before embedding to the data carrier.

In some examples, the copyrighted content can be textual content. Theembedded unique ID can be considered invisible if it does not materiallychange the content. The content can be considered not materially changedif the embedded information does not alter the meaning of the text. Forexample, the original text is “he becomes a monster after seven years,”and the information embedded text is “he has become a ‘monster’ afterseven years.” The information embedded in the added text is notconsidered as materially changed from the original text, since themeaning of the text stays the same. In this example, the unique ID canbe embedded in the quotation marks, or the auxiliary word “has,”according to the techniques described herein. In some embodiments, theunique ID can be embedded in spaces or function words such as articles,prepositions, conjunctions, and auxiliaries, which do not normally alterthe material meaning of textual content.

In some embodiments, a plurality of unique IDs can be used to track theupdates of the textual content. For example, one or more unique IDs canbe generated based on identity information of the copyright holder andtimestamps corresponding to one or more content updates recorded on theblockchain. When a content update is performed and recorded on theblockchain, a unique ID including the corresponding timestamp can beembedded in at least a portion of the updated content. To authenticatethe right holder, the timestamps in the unique IDs extracted from thecopyrighted content can form a timeline of creation and update historyof the content. The timeline can be used as evidence of the contentdevelopment process, and compared to the update history recorded on theblockchain to authenticate authorship of the textual content.

In some embodiments, the unique ID can be embedded in characteristicsinformation of textual or image content. Example characteristicsinformation can include color, brightness, and transparency of text orimage. For example, text or image color can be encoded based on a red,green, and blue (RGB) color model. The unique ID can be embedded toslightly change the RGB value combination not noticeable by naked eyes.As another example, the unique ID can be embedded in YCbCr formattedtext or image, where Y represents the luminance signal, Cb representschrominance blue signal, and Cr represents chrominance red signal. Theluminance signal is relatively insensitive to information embedding,which can be preferably used to invisibly embed the unique ID.

In some embodiments, the unique ID can be embedded in punctuations oftextual content. For example, in the text “after seven years, he becomesa ‘monster’,” the unique ID can be embedded in the encoding of thecommas and quotation marks.

In some embodiments, the unique ID can be embedded in fonts used bytextual content. Fonts can be encoded using Unicode such as UTF-8. TheUTF-8 is based on variable width character encoding, which uses one tofour 8-bit bytes. Embedding the unique ID in some of the bits mayslightly change pixel positions, size, angle, shape of font orpunctuations invisible to the naked eye. For example, pixels of textfonts and punctuations can be encoded with redundancy. Redundancy isnormally added to pixels for error checking in data communications.Redundancy such as check bits can be used to check data integrity at thereceiver end. If the check bits are not consistent with the rest of theinformation bearing pixels when they arrive at the receiver, thereceiver can ask the sender to retransmit the content. The unique ID canbe randomly embedded in redundant pixels or embedded in redundant pixelsin fixed positions. It is to be understood that the unique ID can alsobe invisibly embedded in other hidden characteristics of fonts orpunctuations.

In some embodiments, the unique ID can be embedded in forms or tableswithin or containing the copyrighted content. Those embodiments areespecially suitable for right authentication of text or images insertedin online forms or tables. For example, an online form can be a formdefined in the Hypertext Markup Language (HTML) definition of a webpage(such as by using the “<form>” tag) and rendered by a browser programdisplaying the webpage. Similarly, an online table can be a tabledefined in the Hypertext Markup Language (HTML) definition of a webpage(such as by using the “<table>” tag) and rendered by a browser programdisplaying the webpage. The unique ID can be invisibly embedded invalues associated with color, shade, cell size, or other properties ofthe forms or tables. The unique ID can be extracted for copyrightinfringement identification when the forms or tables containing thecopyrighted content are copied by potential copyright infringers withoutpermission.

In some embodiments, the unique ID can be embedded in background textureof physical or digital data carriers. In some cases, the unique ID canbe embedded to physical media that copyrighted content can be printed orwritten on. For example, the unique ID can be converted into a uniquemesh pattern, which can serve as a digital watermark. A document imagein which copyright information is embedded by superimposing the meshpattern as a document background can then be printed on physical papers.A scan or picture image of the watermarked printed papers can befiltered to extract the digital watermark in copyright authentication.As another example, the unique ID can be embedded as digital watermarkinto hue component of the physical paper, such that it is more tolerantto digital-to-analog conversion and can be more easily extracted.

In some cases, the unique ID can be embedded in electronic media thatcan be used to display or publish copyright content. For example, theunique ID can be embedded in background textures of webpages orelectronic files such as MICROSOFT WORD, POWERPOINT, or ADOBE PDF. Insome cases, the unique ID can be embedded in a film or screen attachedor integrated to an electronic display. In those cases, the embedding ofthe unique ID can take advantage of the texture of the physical paper,the background of the electronic files, or the firm or screen. Thoseembodiments are especially suitable for scenarios that potentialcopyright infringers use scanned copies or pictures taken of thecopyrighted content without permission from the right holder, the uniqueID embedded in the physical media or electronic display that carry thecopyrighted content can be extracted to identify potential copyrightinfringement.

FIG. 4 depicts an example of a content processing process 400 inaccordance with embodiments of this specification. At a high-level, theprocess 400 can be performed by a computing device 401, a blockchaindatabase 414, and a blockchain network 416. The computing device 401 canbe communicably coupled to the blockchain network 416 through wired orwireless communications. Alternatively or additionally, the computingdevice 401 can be a consensus node of the blockchain network 416.

The computing device 401 can generate or update a digital content 402.The digital content can be 402 a copyrighted digital content. Thecomputing device 401 can also perform blockchain-based copyrightauthentication based on blockchain transaction record 404 retrieved froma distributed ledger maintained by the blockchain network 416. In someembodiments, the blockchain transaction record 404 can be retrieved fromthe blockchain database 414 that maintains a complete ledger of theblockchain. Blockchain-based copyright authentication can be performedsimilarly to the description of step 304 of FIG. 3 to provide copyrightauthenticated content 406.

In some embodiments, the blockchain network 416 can be a consortiumblockchain network. In such cases, copyrighted blockchain data can bemanaged by one or more primary nodes of the blockchain network 416. Insome embodiments, the one or more primary nodes can issue a copyrightcertificate to the computing device 401 to authenticate the digitalcontent 402 based on blockchain data stored in the blockchain database412 or the consortium blockchain.

After copyright authentication, the digital content 402 becomescopyright authenticated content 406. The computing device 401 can thengenerate a unique ID 408 associated with copyright information of thedigital content 402. The unique ID 408 can be invisibly embedded in thecopyright authenticated content 406. Generation of unique ID 408 can besimilarly performed as discussed in the description of step 306 of FIG.3. Invisibly embedding the unique ID 408 to copyright authenticatedcontent 406 can be similarly performed as discussed in the descriptionof 308 of FIG. 3.

After invisibly embedding copyright information, the computing device401 can perform information embedded content distribution 410 to one ormore nodes of the blockchain network 416. In some embodiments,blockchain nodes can generate blockchain data corresponding to theinformation embedded content. The blockchain data can include block data(block header) and block transactions (block body). Blockchaintransactions corresponding to information embedded content distribution410 or other content updates can be recorded to update the distributedledger of the blockchain network 416.

FIG. 5 depicts an example of a blockchain transaction record 500 inaccordance with embodiments of this specification. The blockchaintransaction record 500 can be identified and retrieved based on ablockchain transaction ID 502 associated with the transaction. Theblockchain transaction record 500 can include histories of copyrightedcontent such as time of the transaction 504, ownership information 506,sender's address 508, receiver's address 510, fees and prices 512, andblock address corresponding to the transaction 514.

Referring back to FIG. 4, after information embedded contentdistribution 410 is performed, a blockchain database 414 communicablycoupled to the blockchain network 416 can be updated 412. The blockchaindatabase 414 can store updates of the information embedded content andnewly performed transactions associated with the content. The updatedblockchain transaction record 404 can include a longer chain-of-recordsassociated with the digital content 402. As such, it can be morereliably used to authenticate the digital content 402 in futuretransactions.

FIG. 6 depicts an example of a copyright infringement determinationprocess 600 in accordance with embodiments of this specification. At ahigh-level, the process 600 can be performed by a computing device 601,a blockchain network 612, and a blockchain database 610. The process 600can be performed to detect potential copyright infringement based oncopyright information embedded content 602. As discussed in thedescription of FIG. 3, a unique ID can be embedded in copyrightedcontent to produce the information embedded content 602. The unique IDcan be invisibly embedded in pixels, angles, colors, fonts, texture,brightness, spatial or frequency coefficients, or other characteristicsof data carriers based on digital watermarking. Suitable data carrierscan include text, punctuations, images, videos, forms, tables, physicalmedia, electronic media, films or screens.

To police unauthorized use of copyrighted content, the computing device601 can perform unique ID extraction 604 based on at least a portion ofthe information embedded content 602 found online or from a digitalfile. The extracted unique ID 606 can be used to identify transactionrecords associated with the copyrighted content from the blockchainnetwork 612 or the blockchain database 610. If the transaction recordsare successfully identified and the right holder associated with therecords does not match the user of the information embedded content 602,it can be determined that potential copyright infringement may haveoccurred. In some embodiments, the unique ID 606 can also be used toretrieve the latest copyrighted content stored in the blockchaindatabase 610. The retrieved copyrighted content can be used as anauthentic copy to determine whether another copy of the copyrightedcontent is tampered with.

FIG. 7 depicts an example of a process 700 that can be executed inaccordance with embodiments of this specification. For clarity ofpresentation, the description that follows generally describes theexample process 700 in the context of the other figures in thisdescription. However, it will be understood that the example process 700can be performed, for example, by any system, environment, software, andhardware, or a combination of systems, environments, software, andhardware, as appropriate. In some implementations, various steps of theexample process 700 can be run in parallel, in combination, in loops, orin any order.

For convenience, the process 700 will be described as being performed byone or more computing devices, located in one or more locations, andprogrammed appropriately in accordance with this specification. Forexample, a computing device in a computing system, e.g., the computingsystem 106, 108 of FIG. 1, appropriately programmed, can perform theprocess 700.

At 702, the computing device generates a unique ID based on copyrightinformation associated with digital content. The copyright informationand the digital content are recorded on a blockchain of a blockchainnetwork.

At 704, the computing device determines one or more features associatedwith one or more printable materials. The printable materials can be anymaterials that can be used to print digital content. Such materials caninclude paper, textiles, ribbon, film etc. In some cases, more than oneprintable material can form a multi-layer or mixture printable materialand the one or more features can associate with the multi-layer ormixture printable material.

The one or more features can include any features such as texture,curvature, deformation, pattern, color hue, ink, printing technology, orsecurity ribbon associated with the one or more printable materials.

At 706, the computing device converts the unique ID to a digitalwatermark based on the one or more features, the digital watermark notbeing apparent to an unaided human eye when printed on the one or moreprintable materials and enables retrieval of the copyright informationfrom the blockchain based on the unique ID. Because the digitalwatermark is converted from the unique ID, it can carry the copyrightinformation. In some cases, when printed on the one or more printablematerials, the digital watermark is hidden or not visible to naked eyes.As such, the digital watermark can be less discernable by a potentialcopyright infringer to combat the digital watermark.

In some cases, before generating the unique ID, the computing deviceauthenticates that a copyright holder holds a copyright of the digitalcontent based on a blockchain transaction ID associated with atransaction that recorded the digital content in the blockchain.

In some cases, after converting the unique ID to the digital watermark,the computing device prints the digital watermark to the one or moreprintable materials to provide one or more printed content, wherein theone or more features are identifiable from reproduction of the one ormore printed content after the digital watermark is printed.

In some case, the reproduction of the one or more printed contentincludes one or more of copying, scanning, and taking pictures of theone or more printed content.

In some cases, the one or more printable materials include paper.

In some cases, the one or more features include one or more of texture,hue, deformation, ruggedness, and ink attributes associated with thepaper.

In some cases, the copyright information includes one or more of atleast a portion of the digital content or identity information of acopyright holder of the digital content.

In some cases, the digital content is recorded on the blockchain as afirst transaction associated with a first blockchain transaction ID andthe identity information is associated with a second transactionassociated with a second blockchain transaction ID, and wherein thefirst blockchain transaction ID or the second blockchain transaction IDis associated with one or more transaction records associated with thedigital content.

In some cases, the one or more transaction records include one or moreof creatorship, copyright ownership, update history, a timestamp, alocation, or a license associated with the digital content.

In some cases, the computing device digitally signs the unique ID usinga private key assigned to the copyright holder.

In some cases, the unique ID is generated based on one of hashing thecopyright information using a hash function or encrypting the copyrightinformation using a public key assigned to the copyright holder.

In some cases, the unique ID is further generated based on one or moreof a timestamp or an address associated with the copyright information.

In some cases, the computing device converts the unique ID to thedigital watermark is performed based on one or more of a discretewavelet transform, a discrete cosine transform, a singular valuedecomposition, a least significant bit, or undetectable steganography.

FIG. 8 is a diagram of an example of modules of an apparatus 800 inaccordance with embodiments of this specification. The apparatus 800 canbe an example of an embodiment of a client computing device configuredto perform copyright information hiding for copyright protection. Theapparatus 800 can correspond to the embodiments described above, and theapparatus 800 includes the following: a generating module 802 forgenerating a unique ID based on copyright information associated withdigital content, wherein the copyright information and the digitalcontent are recorded on a blockchain of a blockchain network; adetermining module 804 for determining one or more features associatedwith one or more printable materials; a converting module 806 forconverting the unique ID to a digital watermark based on the one or morefeatures, the digital watermark not being apparent to an unaided humaneye when printed on the one or more printable materials and enablingretrieval of the copyright information from the blockchain based on theunique ID.

In an optional embodiment, the apparatus 800 further includes anauthentication sub-module for authenticating, before generating theunique ID, that a copyright holder holds a copyright of the digitalcontent based on a blockchain transaction ID associated with atransaction that recorded the digital content in the blockchain.

In an optional embodiment, the apparatus 800 further includes a printingsub-module for printing, after converting the unique ID, the digitalwatermark to the one or more printable materials to provide one or moreprinted content, wherein the one or more features are identifiable fromreproduction of the one or more printed content after the digitalwatermark is printed.

In an optional embodiment, the reproduction of the one or more printedcontent includes one or more of copying, scanning, and taking picturesof the one or more printed content.

In an optional embodiment, the one or more printable materials includepaper.

In an optional embodiment, the one or more features include one or moreof texture, hue, deformation, ruggedness, and ink attributes associatedwith the paper.

In an optional embodiment, the copyright information includes one ormore of at least a portion of the digital content or identityinformation of a copyright holder of the digital content.

In an optional embodiment, the digital content is recorded on theblockchain as a first transaction associated with a first blockchaintransaction ID and the identity information is associated with a secondtransaction associated with a second blockchain transaction ID, andwherein the first blockchain transaction ID or the second blockchaintransaction ID is associated with one or more transaction recordsassociated with the digital content.

In an optional embodiment, the one or more transaction records includeone or more of creatorship, copyright ownership, update history, atimestamp, a location, or a license associated with the digital content.

In an optional embodiment, the apparatus 800 further includes a digitalsigning sub-module for digitally signing the unique ID using a privatekey assigned to the copyright holder.

In an optional embodiment, the unique ID is generated based on one ofhashing the copyright information using a hash function or encryptingthe copyright information using a public key assigned to the copyrightholder.

In an optional embodiment, the unique ID is further generated based onone or more of a timestamp or an address associated with the copyrightinformation.

In an optional embodiment, converting the unique ID to the digitalwatermark is performed based on one or more of a discrete wavelettransform, a discrete cosine transform, a singular value decomposition,a least significant bit, or undetectable steganography.

The system, apparatus, module, or unit illustrated in the previousembodiments can be implemented by using a computer chip or an entity, orcan be implemented by using a product having a certain function. Atypical embodiment device is a computer, and the computer can be apersonal computer, a laptop computer, a cellular phone, a camera phone,a smartphone, a personal digital assistant, a media player, a navigationdevice, an email receiving and sending device, a game console, a tabletcomputer, a wearable device, or any combination of these devices.

For an embodiment process of functions and roles of each module in theapparatus, references can be made to an embodiment process ofcorresponding steps in the previous method. Details are omitted here forsimplicity.

Because an apparatus embodiment basically corresponds to a methodembodiment, for related parts, references can be made to relateddescriptions in the method embodiment. The previously describedapparatus embodiment is merely an example. The modules described asseparate parts may or may not be physically separate, and partsdisplayed as modules may or may not be physical modules, may be locatedin one position, or may be distributed on a number of network modules.Some or all of the modules can be selected based on actual demands toachieve the objectives of the solutions of the specification. A personof ordinary skill in the art can understand and implement theembodiments of the present application without creative efforts.

The techniques described in this specification produce several technicaleffects. For example, embodiments of the subject matter permitidentification and authentication of creators or right holders ofcopyrighted content based on transaction records stored on a blockchain.The transaction records can be used as evidence to resolve copyrightdispute between alleged right holders. The transaction records can alsobe used for seeking permissions from the authenticated right holders tocopy, modify, license, distribute, or publicly display the copyrightedcontent. Moreover, records on blockchain can be used by right holders toidentify and police copyright infringement.

In some embodiments, a unique ID can be invisibly embedded incopyrighted content as a digital watermark to identify potentialcopyright infringement or illegal changes of copyrighted content.Because the digital watermark is invisibly embedded, it does not visiblyaffect the presentation of the copyrighted content. The invisibledigital watermark can also be difficult to discern and remove bypotential infringers to counter infringement detection.

To police unauthorized use of copyrighted content, the unique ID can beextracted to retrieve transaction records of the copyrighted contentfrom the blockchain. If the transaction records are identified and theuser of the copyrighted content is not the right holder or a licensee ofthe copyrighted content, it can be determined that potential copyrightinfringement may have occurred. In some embodiments, the unique ID canalso be used to retrieve the latest copyrighted content stored on theblockchain to determine whether the copyrighted content is tamperedwith.

The unique ID can also be embedded in physical media, or a screenattached or integrated to an electronic display. When a potentialinfringer uses scanned copy or pictures taken of the copyrighted contentwithout permission from the right holder, the unique ID embedded in thephysical media or electronic display that carry the copyrighted contentcan be extracted to identify potential copyright infringement.

Described embodiments of the subject matter can include one or morefeatures, alone or in combination.

For example, in a first embodiment, a computer-implemented method forhiding copyright information in printable materials, the methodcomprising: generating, by the computing device, a unique ID based oncopyright information associated with digital content, wherein thecopyright information and the digital content are recorded on ablockchain of a blockchain network; determining, by the computingdevice, one or more features associated with one or more printablematerials; and converting, by the computing device, the unique ID to adigital watermark based on the one or more features, the digitalwatermark not being apparent to an unaided human eye when printed on theone or more printable materials and enabling retrieval of the copyrightinformation from the blockchain based on the unique ID.

The foregoing and other described embodiments can each, optionally,include one or more of the following features:

A first feature, combinable with any of the following features, furthercomprising: before generating the unique ID, authenticating, by thecomputing device, that a copyright holder holds a copyright of thedigital content based on a blockchain transaction ID associated with atransaction that recorded the digital content in the blockchain.

A second feature, combinable with any of the previous or followingfeatures, further comprising: after converting the unique ID to thedigital watermark, printing the digital watermark to the one or moreprintable materials to provide one or more printed content, wherein theone or more features are identifiable from reproduction of the one ormore printed content after the digital watermark is printed.

A third feature, combinable with any of the previous or followingfeatures, the reproduction of the one or more printed content includesone or more of copying, scanning, and taking pictures of the one or moreprinted content.

A fourth feature, combinable with any of the previous or followingfeatures, the one or more printable materials include paper.

A fifth feature, combinable with any of the previous or followingfeatures, the one or more features include one or more of texture, hue,deformation, ruggedness, and ink attributes associated with the paper.

A sixth feature, combinable with any of the previous or followingfeatures, the copyright information includes one or more of at least aportion of the digital content or identity information of a copyrightholder of the digital content.

A seventh feature, combinable with any of the previous or followingfeatures, the digital content is recorded on the blockchain as a firsttransaction associated with a first blockchain transaction ID and theidentity information is associated with a second transaction associatedwith a second blockchain transaction ID, and wherein the firstblockchain transaction ID or the second blockchain transaction ID isassociated with one or more transaction records associated with thedigital content.

An eighth feature, combinable with any of the previous or followingfeatures, the one or more transaction records include one or more ofcreatorship, copyright ownership, update history, a timestamp, alocation, or a license associated with the digital content.

A ninth feature, combinable with any of the previous or followingfeatures, further comprising digitally signing the unique ID using aprivate key assigned to the copyright holder.

A tenth feature, combinable with any of the previous or followingfeatures, the unique ID is generated based on one of hashing thecopyright information using a hash function or encrypting the copyrightinformation using a public key assigned to the copyright holder.

An eleventh feature, combinable with any of the previous or followingfeatures, the unique ID is further generated based on one or more of atimestamp or an address associated with the copyright information.

A twelfth feature, combinable with any of the previous or followingfeatures, converting the unique ID to the digital watermark is performedbased on one or more of a discrete wavelet transform, a discrete cosinetransform, a singular value decomposition, a least significant bit, orundetectable steganography.

Embodiments of the subject matter and the actions and operationsdescribed in this specification can be implemented in digital electroniccircuitry, in tangibly-embodied computer software or firmware, incomputer hardware, including the structures disclosed in thisspecification and their structural equivalents, or in combinations ofone or more of them. Embodiments of the subject matter described in thisspecification can be implemented as one or more computer programs, e.g.,one or more modules of computer program instructions, encoded on acomputer program carrier, for execution by, or to control the operationof, data processing apparatus. For example, a computer program carriercan include one or more computer-readable storage media that haveinstructions encoded or stored thereon. The carrier may be a tangiblenon-transitory computer-readable medium, such as a magnetic, magnetooptical, or optical disk, a solid state drive, a random access memory(RAM), a read-only memory (ROM), or other types of media. Alternatively,or in addition, the carrier may be an artificially generated propagatedsignal, e.g., a machine-generated electrical, optical, orelectromagnetic signal that is generated to encode information fortransmission to suitable receiver apparatus for execution by a dataprocessing apparatus. The computer storage medium can be or be part of amachine-readable storage device, a machine-readable storage substrate, arandom or serial access memory device, or a combination of one or moreof them. A computer storage medium is not a propagated signal.

A computer program, which may also be referred to or described as aprogram, software, a software application, an app, a module, a softwaremodule, an engine, a script, or code, can be written in any form ofprogramming language, including compiled or interpreted languages, ordeclarative or procedural languages; and it can be deployed in any form,including as a stand-alone program or as a module, component, engine,subroutine, or other unit suitable for executing in a computingenvironment, which environment may include one or more computersinterconnected by a data communication network in one or more locations.

A computer program may, but need not, correspond to a file in a filesystem. A computer program can be stored in a portion of a file thatholds other programs or data, e.g., one or more scripts stored in amarkup language document, in a single file dedicated to the program inquestion, or in multiple coordinated files, e.g., files that store oneor more modules, sub programs, or portions of code.

Processors for execution of a computer program include, by way ofexample, both general- and special-purpose microprocessors, and any oneor more processors of any kind of digital computer. Generally, aprocessor will receive the instructions of the computer program forexecution as well as data from a non-transitory computer-readable mediumcoupled to the processor.

The term “data processing apparatus” encompasses all kinds ofapparatuses, devices, and machines for processing data, including by wayof example a programmable processor, a computer, or multiple processorsor computers. Data processing apparatus can include special-purposelogic circuitry, e.g., an FPGA (field programmable gate array), an ASIC(application specific integrated circuit), or a GPU (graphics processingunit). The apparatus can also include, in addition to hardware, codethat creates an execution environment for computer programs, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, or a combination of one or moreof them.

The processes and logic flows described in this specification can beperformed by one or more computers or processors executing one or morecomputer programs to perform operations by operating on input data andgenerating output. The processes and logic flows can also be performedby special-purpose logic circuitry, e.g., an FPGA, an ASIC, or a GPU, orby a combination of special-purpose logic circuitry and one or moreprogrammed computers.

Computers suitable for the execution of a computer program can be basedon general or special-purpose microprocessors or both, or any other kindof central processing unit. Generally, a central processing unit willreceive instructions and data from a read only memory or a random accessmemory or both. Elements of a computer can include a central processingunit for executing instructions and one or more memory devices forstoring instructions and data. The central processing unit and thememory can be supplemented by, or incorporated in, special-purpose logiccircuitry.

Generally, a computer will also include, or be operatively coupled toreceive data from or transfer data to one or more storage devices. Thestorage devices can be, for example, magnetic, magneto optical, oroptical disks, solid state drives, or any other type of non-transitory,computer-readable media. However, a computer need not have such devices.Thus, a computer may be coupled to one or more storage devices, such as,one or more memories, that are local and/or remote. For example, acomputer can include one or more local memories that are integralcomponents of the computer, or the computer can be coupled to one ormore remote memories that are in a cloud network. Moreover, a computercan be embedded in another device, e.g., a mobile telephone, a personaldigital assistant (PDA), a mobile audio or video player, a game console,a Global Positioning System (GPS) receiver, or a portable storagedevice, e.g., a universal serial bus (USB) flash drive, to name just afew.

Components can be “coupled to” each other by being commutatively such aselectrically or optically connected to one another, either directly orvia one or more intermediate components. Components can also be “coupledto” each other if one of the components is integrated into the other.For example, a storage component that is integrated into a processor(e.g., an L2 cache component) is “coupled to” the processor.

To provide for interaction with a user, embodiments of the subjectmatter described in this specification can be implemented on, orconfigured to communicate with, a computer having a display device,e.g., a LCD (liquid crystal display) monitor, for displaying informationto the user, and an input device by which the user can provide input tothe computer, e.g., a keyboard and a pointing device, e.g., a mouse, atrackball or touchpad. Other kinds of devices can be used to provide forinteraction with a user as well; for example, feedback provided to theuser can be any form of sensory feedback, e.g., visual feedback,auditory feedback, or tactile feedback; and input from the user can bereceived in any form, including acoustic, speech, or tactile input. Inaddition, a computer can interact with a user by sending documents toand receiving documents from a device that is used by the user; forexample, by sending web pages to a web browser on a user's device inresponse to requests received from the web browser, or by interactingwith an app running on a user device, e.g., a smartphone or electronictablet. Also, a computer can interact with a user by sending textmessages or other forms of message to a personal device, e.g., asmartphone that is running a messaging application, and receivingresponsive messages from the user in return.

This specification uses the term “configured to” in connection withsystems, apparatus, and computer program components. For a system of oneor more computers to be configured to perform particular operations oractions means that the system has installed on it software, firmware,hardware, or a combination of them that in operation cause the system toperform the operations or actions. For one or more computer programs tobe configured to perform particular operations or actions means that theone or more programs include instructions that, when executed by dataprocessing apparatus, cause the apparatus to perform the operations oractions. For special-purpose logic circuitry to be configured to performparticular operations or actions means that the circuitry has electroniclogic that performs the operations or actions.

While this specification contains many specific embodiment details,these should not be construed as limitations on the scope of what isbeing claimed, which is defined by the claims themselves, but rather asdescriptions of features that may be specific to particular embodiments.Certain features that are described in this specification in the contextof separate embodiments can also be realized in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiments can also be realized in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially be claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claim may be directed to a subcombination orvariation of a subcombination.

Similarly, while operations are depicted in the drawings and recited inthe claims in a particular order, this should not be understood asrequiring that such operations be performed in the particular ordershown or in sequential order, or that all illustrated operations beperformed, to achieve desirable results. In certain circumstances,multitasking and parallel processing may be advantageous. Moreover, theseparation of various system modules and components in the embodimentsdescribed above should not be understood as requiring such separation inall embodiments, and it should be understood that the described programcomponents and systems can generally be integrated together in a singlesoftware product or packaged into multiple software products.

Particular embodiments of the subject matter have been described. Otherembodiments are within the scope of the following claims. For example,the actions recited in the claims can be performed in a different orderand still achieve desirable results. As one example, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In some cases, multitasking and parallel processing may beadvantageous.

1. A computer-implemented method for hiding copyright information inprintable materials, the method comprising: generating, by a computingdevice, a unique identifier (ID) based on copyright informationassociated with digital content, wherein the copyright information andthe digital content are recorded on a blockchain of a blockchainnetwork, and wherein the copyright information comprises one or more ofa change in copyright ownership associated with the digital content, amodification to the digital content, an update to the digital content,and a change in licensing associated with the digital content;determining, by the computing device, one or more features associatedwith one or more printable materials; and converting, by the computingdevice, the unique ID to a digital watermark based on the one or morefeatures; and printing, to the one or more printable materials, aprinted version of the digital content, including printing the digitalwatermark, the printed digital watermark not being apparent to anunaided human eye, wherein the printed digital watermark enablesretrieval of the copyright information from the blockchain based on theunique ID.
 2. The computer-implemented method of claim 1, furthercomprising: before generating the unique ID, authenticating, by thecomputing device, that a copyright holder holds a copyright of thedigital content based on a blockchain transaction ID associated with atransaction that recorded the digital content in the blockchain.
 3. Thecomputer-implemented method of claim 1 wherein the one or more featuresare identifiable from reproduction of the printed version of the digitalcontent after the digital watermark is printed.
 4. Thecomputer-implemented method of claim 3, wherein the reproduction of theprinted version of the digital content includes one or more of copying,scanning, and taking pictures of the printed version of the digitalcontent.
 5. The computer-implemented method of claim 4, wherein the oneor more printable materials include paper.
 6. The computer-implementedmethod of claim 5, wherein the one or more features include one or moreof texture, hue, deformation, ruggedness, and ink attributes associatedwith the paper.
 7. The computer-implemented method of claim 1, whereinthe copyright information includes one or more of at least a portion ofthe digital content or identity information of a copyright holder of thedigital content.
 8. The computer-implemented method of claim 7, whereinthe digital content is recorded on the blockchain as a first transactionassociated with a first blockchain transaction ID and the identityinformation is associated with a second transaction associated with asecond blockchain transaction ID, and wherein the first blockchaintransaction ID or the second blockchain transaction ID is associatedwith one or more transaction records associated with the digitalcontent.
 9. The computer-implemented method of claim 8, wherein the oneor more transaction records include one or more of creatorship,copyright ownership, update history, a timestamp, a location, or alicense associated with the digital content.
 10. Thecomputer-implemented method of claim 1, further comprising digitallysigning the unique ID using a private key assigned to a copyright holderof the digital content.
 11. The computer-implemented method of claim 1,wherein the unique ID is generated based on one of hashing the copyrightinformation using a hash function or encrypting the copyrightinformation using a public key assigned to a copyright holder of thedigital content.
 12. The computer-implemented method of claim 1, whereinthe unique ID is further generated based on one or more of a timestampor an address associated with the copyright information.
 13. Thecomputer-implemented method of claim 1, wherein converting the unique IDto the digital watermark is performed based on one or more of a discretewavelet transform, a discrete cosine transform, a singular valuedecomposition, a least significant bit, or undetectable steganography.14. A non-transitory, computer-readable storage medium storing one ormore instructions executable by a computer system to perform operationsfor hiding copyright information in printable materials, the operationscomprising: generating, by a computing device, a unique identifier (ID)based on copyright information associated with digital content, whereinthe copyright information and the digital content are recorded on ablockchain of a blockchain network, and wherein the copyrightinformation comprises one or more of a change in copyright ownershipassociated with the digital content, a modification to the digitalcontent, an update to the digital content, and a change in licensingassociated with the digital content; determining, by the computingdevice, one or more features associated with one or more printablematerials; and converting, by the computing device, the unique ID to adigital watermark based on the one or more features; and printing, tothe one or more printable materials, a printed version of the digitalcontent, including printing the digital watermark, the printed digitalwatermark not being apparent to an unaided human eye, wherein theprinted digital watermark enables retrieval of the copyright informationfrom the blockchain based on the unique ID.
 15. The non-transitory,computer-readable storage medium of claim 14, the operations furthercomprising: before generating the unique ID, authenticating, by thecomputing device, that a copyright holder holds a copyright of thedigital content based on a blockchain transaction ID associated with atransaction that recorded the digital content in the blockchain.
 16. Thenon-transitory, computer-readable storage medium of claim 14, whereinthe one or more features are identifiable from reproduction of theprinted version of the digital content after the digital watermark isprinted.
 17. The non-transitory, computer-readable storage medium ofclaim 16, wherein the reproduction of the printed version of the digitalcontent includes one or more of copying, scanning, and taking picturesof the printed version of the digital content.
 18. The non-transitory,computer-readable storage medium of claim 14, wherein the copyrightinformation includes one or more of at least a portion of the digitalcontent or identity information of a copyright holder of the digitalcontent, wherein the digital content is recorded on the blockchain as afirst transaction associated with a first blockchain transaction ID andthe identity information is associated with a second transactionassociated with a second blockchain transaction ID, and wherein thefirst blockchain transaction ID or the second blockchain transaction IDis associated with one or more transaction records associated with thedigital content.
 19. The non-transitory, computer-readable storagemedium of claim 18, wherein the one or more transaction records includeone or more of creatorship, copyright ownership, update history, atimestamp, a location, or a license associated with the digital content.20. The non-transitory, computer-readable storage medium of claim 14,the operations further comprising digitally signing the unique ID usinga private key assigned to the copyright holder.
 21. The non-transitory,computer-readable storage medium of claim 14, wherein the unique ID isgenerated based on one of hashing the copyright information using a hashfunction or encrypting the copyright information using a public keyassigned to a copyright holder of the digital content.
 22. Thenon-transitory, computer-readable storage medium of claim 14, whereinthe unique ID is further generated based on one or more of a timestampor an address associated with the copyright information.
 23. Thenon-transitory, computer-readable storage medium of claim 14, whereinconverting the unique ID to the digital watermark is performed based onone or more of a discrete wavelet transform, a discrete cosinetransform, a singular value decomposition, a least significant bit, orundetectable steganography.
 24. A computer-implemented system,comprising: one or more computers; and one or more computer memorydevices interoperably coupled with the one or more computers and havingtangible, non-transitory, machine-readable media storing one or moreinstructions that, when executed by the one or more computers, performone or more operations for hiding copyright information in printablematerials, the operations comprising: generating, by a computing device,a unique identifier (ID) based on copyright information associated withdigital content, wherein the copyright information and the digitalcontent are recorded on a blockchain of a blockchain network, andwherein the copyright information comprises one or more of a change incopyright ownership associated with the digital content, a modificationto the digital content, an update to the digital content, and a changein licensing associated with the digital content; determining, by thecomputing device, one or more features associated with one or moreprintable materials; and converting, by the computing device, the uniqueID to a digital watermark based on the one or more features; andprinting, to the one or more printable materials, a printed version ofthe digital content, including printing the digital watermark, theprinted digital watermark not being apparent to an unaided human eye,wherein the printed digital watermark enables retrieval of the copyrightinformation from the blockchain based on the unique ID.
 25. The systemof claim 24, the operations further comprising: before generating theunique ID, authenticating, by the computing device, that a copyrightholder holds a copyright of the digital content based on a blockchaintransaction ID associated with a transaction that recorded the digitalcontent in the blockchain.
 26. The system of claim 24, wherein the oneor more features are identifiable from reproduction of the printedversion of the digital content after the digital watermark is printed.27. The system of claim 26, wherein the reproduction of the printedversion of the digital content includes one or more of copying,scanning, and taking pictures of the printed version of the digitalcontent. 28.-30. (canceled)
 31. The computer-implemented method of claim1, further comprising: generating a plurality of unique IDs based on thecopyright information, each of the plurality of unique IDs comprising acorresponding timestamp; converting the unique IDs to a plurality ofdigital watermarks; and printing the plurality of digital watermarks tothe one or more printable materials, the plurality of digital watermarksproviding a timeline of updates associated with the digital content. 32.The non-transitory, computer-readable storage medium of claim 14, theoperations further comprising: generating a plurality of unique IDsbased on the copyright information, each of the plurality of unique IDscomprising a corresponding timestamp; converting the unique IDs to aplurality of digital watermarks; and printing the plurality of digitalwatermarks to the one or more printable materials, the plurality ofdigital watermarks providing a timeline of updates associated with thedigital content.
 33. The system of claim 24, the operations furthercomprising: generating a plurality of unique IDs based on the copyrightinformation, each of the plurality of unique IDs comprising acorresponding timestamp; converting the unique IDs to a plurality ofdigital watermarks; and printing the plurality of digital watermarks tothe one or more printable materials, the plurality of digital watermarksproviding a timeline of updates associated with the digital content.